Sole proprietorship guide in Aarau: rules, deadlines, best practice
Delegate, digitalise or do it all yourself? Around sole proprietorship in Aarau, every SME draws its own line. The reference points below — federal law, cantonal practice and lessons from the field — help you place the cursor well.
Choosing the structure: Sàrl, SA or sole proprietorship
Settling in Aarau does not change federal law, but the canton shapes what follows: profit and capital tax rates, family allowances, possible start-up support. Comparing seriously before fixing the seat can pay off — moving a company later costs more.
From day one, three administrative tracks open: affiliation to an AHV compensation office, review of VAT liability (CHF 100,000 threshold) and setting up the accounts. Handling sole proprietorship from the first month costs far less than reconstructing a whole year in December.
Swiss VAT: rates, threshold and filings
Exports, services abroad, acquisition tax: as soon as anything international enters the picture, VAT gets demanding (place of supply, acquisition tax on services). Better to set the rules once with a professional than to correct three financial years.
For an SME in Aarau, electronic filing of VAT returns has been mandatory since 1 January 2025; the tax administration's online portal is also where extensions are requested and past periods consulted. Combined with accounts that prepare the return automatically, sole proprietorship stops being a quarterly chore.
Salaries and social contributions: the rates to know
Family allowances are financed by the employer through a cantonal compensation fund — rates and amounts vary from canton to canton, including in Aarau. They come on top of the federal social insurances and appear on every payslip.
A thirteenth salary, where agreed, is accrued month by month — forget it and December reveals a charge of one-twelfth of the payroll, in Aarau as everywhere.
Digitalising sole proprietorship: what actually works
Security is part of digitalisation: named access, tested backups, encryption of sensitive data. A digital accounting file is protected like a safe — because it is one.
The selection criterion for a tool is not the length of its feature list but the robustness of the daily flow: reliable bank imports, VAT computed correctly (8.1 / 2.6 / 3.8%), a complete audit trail from document to entry, and a clean export for the auditor or fiduciary. Everything else is secondary.
Aarau: what changes, what does not
Aarau (postal code 5000, canton Aargau) applies the same federal rules as the rest of the country: what changes in Aarau are the cantonal counterparts — tax administration, compensation office, commercial register.
Federal deadlines do not move in Aarau: VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5000 changes nothing about those rules, only the sender's address.
Frequently asked questions
Can sole proprietorship be automated with AI?
Largely, yes: automatic document reading, posting suggestions, bank reconciliation via QR references and VAT exports. Human approval remains essential — AI prepares, the professional checks. That is exactly how MyFiducia.ai approaches sole proprietorship.
Do you need a fiduciary for sole proprietorship, or can you do it yourself?
Both are defensible. Below CHF 500,000 of revenue, a sole proprietorship may keep simplified accounts itself. As soon as payroll, VAT and a closing with tax stakes are involved, professional support prevents mistakes that cost more than the fees. With a shared platform, the fiduciary does not even need to be in Aarau.
What are the current Swiss VAT rates?
Since 1 January 2024: 8.1% (standard), 2.6% (reduced — for example food and medicines) and 3.8% (accommodation). Returns must be filed and paid within 60 days after the period ends (quarterly under the effective method, semi-annually under the net tax rate method). These federal rates apply unchanged in Aarau.
What is the difference between a limited and an ordinary audit?
The ordinary audit applies to companies exceeding, for two consecutive years, two of three thresholds: CHF 20 million balance sheet total, CHF 40 million revenue, 250 full-time positions. Others fall under the limited audit, and those with no more than ten full-time positions on annual average can opt out with all shareholders' consent. These federal thresholds do not depend on the registered seat — in Aarau as anywhere.
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In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates sole proprietorship for businesses in Aarau: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
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